A variety of surgical procedures use tensioning elements to effect repair of a body organ. For example, heart disease can be treated with such tensioning elements, which can be used to replace and/or assist the functioning of native structures.
One type of heart disease occurs when a ventricle becomes dilated. Ventricular dilatation can reduce the heart's ability to pump blood, and can lead to a significant increase in wall tension and/or stress. Such wall tension and/or stress can lead to further dilatation, which can lead to heart failure. One method of treating this condition is to apply tensioning elements to the heart wall which absorb some of the tension produced during heart operation, thereby reducing the tension in the heart wall. Determining the proper tension to apply via the tensioning elements can be difficult.
Heart valve disease is a widespread condition in which one or more of the valves of the heart fails to function properly. Diseased heart valves may be categorized as either stenotic, wherein the valve does not open sufficiently to allow adequate forward flow of blood through the valve, and/or incompetent, wherein the valve does not close completely, causing excessive backward flow of blood through the valve when the valve is closed. Valve disease can be severely debilitating and even fatal if left untreated. Valve disease often involves damaged chordae tendineae, which are thread-like bands of fibrous connective tissue that attach to the mitral or tricuspid valve at one end and to the papillary muscles or the ventricular wall at the other end.
Various surgical techniques may be used to repair a diseased or damaged heart and/or heart valve. One method for treating defective valves is through repair or reconstruction. A repair technique that has been shown to be effective in treating incompetence is annuloplasty, in which the effective size and/or shape of the valve annulus is modified by securing a repair segment, such as an annuloplasty ring, around the heart valve annulus. For example, the valve annulus may be contracted by attaching a prosthetic annuloplasty repair segment or ring to an interior wall of the heart around the valve annulus. The annuloplasty ring is designed to support the functional changes that occur during the cardiac cycle: maintaining coaptation and valve integrity to prevent reverse flow while permitting good hemodynamics during forward flow.
In many diseased valves, the chordae tendineae are either ruptured, otherwise damaged, or of an improper length. When chordae tendineae are too long, too short, or otherwise damaged, the corresponding tricuspid or mitral valve to which they are attached typically may fail to close properly. For example, chordae tendineae which are ruptured or are too long allow a valve to prolapse, wherein one or more valve leaflets swing backward past their proper closed position. This can lead to regurgitation, which is the unwanted backflow of blood from a ventricle to an atrium resulting from imperfections in the valve. When the valve allows such backward flow into an atrium, the corresponding ventricle must pump progressively harder to circulate blood throughout the body, which in turn promotes congestive heart failure.
Repairing and/or replacing dysfunctional chordae tendineae has been performed for some time. The techniques for such repair are often complicated due to the difficulties in accessing the surgical site, in identifying the dysfunctional chordae tendineae, and in determining the proper length for the repaired and/or replacement chordae tendineae. Determining the proper length for replacement chordae tendineae can be a complex procedure. Additionally, prior methods for replacing and adjusting the length of the chordae tendineae often involved making such adjustments on an arrested heart, whereas the final test of the appropriateness of the adjusted length is typically performed while the heart is beating. According, what has been needed is a method of adjusting replacement chordae lengths on a beating heart.
Accordingly, there has been a need for an improved apparatus, system, and method to apply and adjust tensioning members on and/or in a body organ, including the repair and replacement of chordae tendineae on heart valves. The present invention satisfies one or more of these needs.